Added support of empty ranges (#19)

* Date range may empty, ends exactly at start

* Update CHANGELOG

Author: slavcodev

CHANGELOG.md

@@ -18,6 +18,9 @@ Security - in case of vulnerabilities.
 
 _TBD_
 
+### Changed
+- Added support of empty ranges, allowing you to use the end time exactly the same as the start time. ([#18](../../pull/19)).
+
 ## [0.4.0] 2018-02-16
 
 ### Added

src/States/FiniteState.php

@@ -26,7 +26,7 @@ final class FiniteState extends RangeState
      */
     public function __construct(DateTimeInterface $startDate, DateTimeInterface $endDate)
     {
-        if ($endDate <= $startDate) {
+        if ($endDate < $startDate) {
             throw new DateRangeException('Invalid end date, must be after start');
         }
 

tests/States/FiniteRangeTest.php

@@ -78,12 +78,14 @@ public function guardRangeSequence()
 
     /**
      * @test
+     * @depends checkFiniteState
      */
-    public function guardRangeDatesDifference()
+    public function rangeMayBeEmptyWhenEndsExactlyAtStart()
     {
-        $this->expectException(DateRangeException::class);
-        $this->expectExceptionMessage('Invalid end date, must be after start');
-
-        new FiniteState($this->tomorrow, $this->tomorrow);
+        $subject = new FiniteState($this->tomorrow, $this->tomorrow);
+        self::assertTrue($subject->hasStartDate());
+        self::assertTrue($subject->hasEndDate());
+        self::assertSame($this->tomorrow, $subject->getStartDate());
+        self::assertSame($this->tomorrow, $subject->getEndDate());
     }
 }